From bde59c475e0883e4c4294bcd9b9c7e08ae18c828 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 6 Sep 2017 15:01:42 +0200 Subject: [PATCH] mac80211: fix deadlock in driver-managed RX BA session start When an RX BA session is started by the driver, and it has to tell mac80211 about it, the corresponding bit in tid_rx_manage_offl gets set and the BA session work is scheduled. Upon testing this bit, it will call __ieee80211_start_rx_ba_session(), thus deadlocking as it already holds the ampdu_mlme.mtx, which that acquires again. Fix this by adding ___ieee80211_start_rx_ba_session(), a version of the function that requires the mutex already held. Cc: stable@vger.kernel.org Fixes: 699cb58c8a52 ("mac80211: manage RX BA session offload without SKB queue") Reported-by: Matteo Croce Signed-off-by: Johannes Berg --- net/mac80211/agg-rx.c | 32 +++++++++++++++++++++----------- net/mac80211/ht.c | 6 +++--- net/mac80211/ieee80211_i.h | 4 ++++ 3 files changed, 28 insertions(+), 14 deletions(-) diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c index 2b36eff5d97e..2849a1fc41c5 100644 --- a/net/mac80211/agg-rx.c +++ b/net/mac80211/agg-rx.c @@ -245,10 +245,10 @@ static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *d ieee80211_tx_skb(sdata, skb); } -void __ieee80211_start_rx_ba_session(struct sta_info *sta, - u8 dialog_token, u16 timeout, - u16 start_seq_num, u16 ba_policy, u16 tid, - u16 buf_size, bool tx, bool auto_seq) +void ___ieee80211_start_rx_ba_session(struct sta_info *sta, + u8 dialog_token, u16 timeout, + u16 start_seq_num, u16 ba_policy, u16 tid, + u16 buf_size, bool tx, bool auto_seq) { struct ieee80211_local *local = sta->sdata->local; struct tid_ampdu_rx *tid_agg_rx; @@ -267,7 +267,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, ht_dbg(sta->sdata, "STA %pM requests BA session on unsupported tid %d\n", sta->sta.addr, tid); - goto end_no_lock; + goto end; } if (!sta->sta.ht_cap.ht_supported) { @@ -275,14 +275,14 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, "STA %pM erroneously requests BA session on tid %d w/o QoS\n", sta->sta.addr, tid); /* send a response anyway, it's an error case if we get here */ - goto end_no_lock; + goto end; } if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) { ht_dbg(sta->sdata, "Suspend in progress - Denying ADDBA request (%pM tid %d)\n", sta->sta.addr, tid); - goto end_no_lock; + goto end; } /* sanity check for incoming parameters: @@ -296,7 +296,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, ht_dbg_ratelimited(sta->sdata, "AddBA Req with bad params from %pM on tid %u. policy %d, buffer size %d\n", sta->sta.addr, tid, ba_policy, buf_size); - goto end_no_lock; + goto end; } /* determine default buffer size */ if (buf_size == 0) @@ -311,7 +311,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, buf_size, sta->sta.addr); /* examine state machine */ - mutex_lock(&sta->ampdu_mlme.mtx); + lockdep_assert_held(&sta->ampdu_mlme.mtx); if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) { if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) { @@ -415,15 +415,25 @@ end: __clear_bit(tid, sta->ampdu_mlme.unexpected_agg); sta->ampdu_mlme.tid_rx_token[tid] = dialog_token; } - mutex_unlock(&sta->ampdu_mlme.mtx); -end_no_lock: if (tx) ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid, dialog_token, status, 1, buf_size, timeout); } +void __ieee80211_start_rx_ba_session(struct sta_info *sta, + u8 dialog_token, u16 timeout, + u16 start_seq_num, u16 ba_policy, u16 tid, + u16 buf_size, bool tx, bool auto_seq) +{ + mutex_lock(&sta->ampdu_mlme.mtx); + ___ieee80211_start_rx_ba_session(sta, dialog_token, timeout, + start_seq_num, ba_policy, tid, + buf_size, tx, auto_seq); + mutex_unlock(&sta->ampdu_mlme.mtx); +} + void ieee80211_process_addba_request(struct ieee80211_local *local, struct sta_info *sta, struct ieee80211_mgmt *mgmt, diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c index 4cba7fca10d4..d6d0b4201e40 100644 --- a/net/mac80211/ht.c +++ b/net/mac80211/ht.c @@ -351,9 +351,9 @@ void ieee80211_ba_session_work(struct work_struct *work) if (test_and_clear_bit(tid, sta->ampdu_mlme.tid_rx_manage_offl)) - __ieee80211_start_rx_ba_session(sta, 0, 0, 0, 1, tid, - IEEE80211_MAX_AMPDU_BUF, - false, true); + ___ieee80211_start_rx_ba_session(sta, 0, 0, 0, 1, tid, + IEEE80211_MAX_AMPDU_BUF, + false, true); if (test_and_clear_bit(tid + IEEE80211_NUM_TIDS, sta->ampdu_mlme.tid_rx_manage_offl)) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 2197c62a0a6e..9675814f64db 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1760,6 +1760,10 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, u8 dialog_token, u16 timeout, u16 start_seq_num, u16 ba_policy, u16 tid, u16 buf_size, bool tx, bool auto_seq); +void ___ieee80211_start_rx_ba_session(struct sta_info *sta, + u8 dialog_token, u16 timeout, + u16 start_seq_num, u16 ba_policy, u16 tid, + u16 buf_size, bool tx, bool auto_seq); void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta, enum ieee80211_agg_stop_reason reason); void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata, -- 2.20.1